U.S. patent application number 13/824612 was filed with the patent office on 2013-07-25 for counter electrode for dye-sensitized solar cell and manufacturing method thereof.
This patent application is currently assigned to OCEAN'S KING LIGHTING SCIENCE & TECHNOLOGY CO., LTD.. The applicant listed for this patent is Jixing Chen, Hui Huang, Ping Wang, Mingjie Zhou. Invention is credited to Jixing Chen, Hui Huang, Ping Wang, Mingjie Zhou.
Application Number | 20130186465 13/824612 |
Document ID | / |
Family ID | 45891794 |
Filed Date | 2013-07-25 |
United States Patent
Application |
20130186465 |
Kind Code |
A1 |
Zhou; Mingjie ; et
al. |
July 25, 2013 |
COUNTER ELECTRODE FOR DYE-SENSITIZED SOLAR CELL AND MANUFACTURING
METHOD THEREOF
Abstract
The invention relates to a counter electrode for a
dye-sensitized solar cell and a manufacturing method thereof. The
counter electrode comprises a conductive substrate and an acid
doped polyaniline layer coated on at least one surface of the
conductive substrate. The conductivity of the counter electrode is
increased, the recombination probability of I.sub.3.sup.- and a
conduction band electron is decreased, the bond strength of the
acid doped polyaniline layer and the conductive substrate is
enhanced, the electronic transmission rate and the conductivity of
the counter electrode for the external circuit are further
increased, and the production cost is reduced. The manufacturing
method can simplify the production process, produce the stable
performance counter electrode, increase the production efficiency,
and reduce the requirement for production equipment, thus suitable
for industrial production.
Inventors: |
Zhou; Mingjie; (Shenzhen,
CN) ; Wang; Ping; (Shenzhen, CN) ; Huang;
Hui; (Shenzhen, CN) ; Chen; Jixing; (Shenzhen,
CN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Zhou; Mingjie
Wang; Ping
Huang; Hui
Chen; Jixing |
Shenzhen
Shenzhen
Shenzhen
Shenzhen |
|
CN
CN
CN
CN |
|
|
Assignee: |
OCEAN'S KING LIGHTING SCIENCE &
TECHNOLOGY CO., LTD.
Shenzhen, Guangdong
CN
|
Family ID: |
45891794 |
Appl. No.: |
13/824612 |
Filed: |
September 27, 2010 |
PCT Filed: |
September 27, 2010 |
PCT NO: |
PCT/CN2010/077366 |
371 Date: |
March 18, 2013 |
Current U.S.
Class: |
136/256 ;
438/98 |
Current CPC
Class: |
H01L 31/022425 20130101;
H01L 51/0035 20130101; Y02P 70/50 20151101; H01G 9/2031 20130101;
H01G 9/2022 20130101; Y02E 10/542 20130101; Y02P 70/521 20151101;
H01G 9/2059 20130101 |
Class at
Publication: |
136/256 ;
438/98 |
International
Class: |
H01L 31/0224 20060101
H01L031/0224 |
Claims
1. A counter electrode for dye-sensitized solar cell, comprising a
conductive substrate, wherein an acid-doped polyaniline layer is
coated on at least one surface of the conductive substrate.
2. The counter electrode for dye-sensitized solar cell according to
claim 1, wherein the acid-doped polyaniline layer has a thickness
of 20 nm-5 .mu.m.
3. The counter electrode for dye-sensitized solar cell according to
claim 1, wherein the acid in the acid-doped polyaniline layer is an
organic functional protonic acid.
4. The counter electrode for dye-sensitized solar cell according to
claim 1, wherein the acid in the acid-doped polyaniline layer is a
sulfonic acid and/or citric acid.
5. The counter electrode for dye-sensitized solar cell according to
claim 4, wherein the sulfonic acid is at least one of
camphorsulfonic acid, dodecylsulfonic acid, sulfosalicylic acid,
p-styrene sulfonic acid, p-toluene sulfonic acid,
naphthalenesulfonic acid, dinonylnaphthalenesulfonic acid, dioctyl
sulfosuccinate and sulfanilic acid.
6. A method for preparing a counter electrode for dye-sensitized
solar cell, comprising the steps of: providing an acid-doped
polyaniline solution and a conductive substrate; and coating the
acid-doped polyaniline solution on at least one surface of the
conductive substrate, and drying to give the counter electrode for
dye-sensitized solar cell having an acid-doped polyaniline layer
coated on a surface thereof.
7. The method for preparing a counter electrode for dye-sensitized
solar cell according to claim 6, wherein the process for obtaining
the acid-doped polyaniline solution comprises: providing an eigen
state polyaniline, an acid and a solvent; mixing the eigen state
polyaniline and the acid, heating in a water bath and/or
sonicating, washing, filtering, and drying to give an acid-doped
polyaniline precursor; and dissolving the acid-doped polyaniline
precursor in a solvent, and diluting to give the acid-doped
polyaniline solution.
8. The method for preparing a counter electrode for dye-sensitized
solar cell according to claim 7, wherein: the eigen state
polyaniline and the acid are mixed in a mass ratio of 1:2-1:5; and
the mass concentration of the acid-doped polyaniline in the
acid-doped polyaniline solution is 1-20%.
9. The method for preparing a counter electrode for dye-sensitized
solar cell according to claim 7, wherein: the solvent is at least
one of de-ionized water, N-methyl pyrrolidone, methanol,
iso-propanol, n-butanol and ethanol; and the acid is at least one
of camphorsulfonic acid, dodecylsulfonic acid, sulfosalicylic acid,
p-styrene sulfonic acid, p-toluene sulfonic acid,
naphthalenesulfonic acid, dinonylnaphthalenesulfonic acid, dioctyl
sulfosuccinate, sulfanilic acid, citric acid, hydrochloric acid,
sulfuric acid and perchloric acid.
10. The method for preparing a counter electrode for dye-sensitized
solar cell according to claim 6, wherein: the method further
comprises conducting surface treatment to the conductive substrate,
wherein the surface treatment conducted to the conductive substrate
is at least one of oxygen plasma treatment, uv-ozone treatment,
aqua regia treatment, hydrogen peroxide treatment, acid treatment
and chemical polishing treatment; a method for coating the
acid-doped polyaniline solution on the conductive substrate is spin
coating, scrape coating, silkscreen coating, or spray coating; and
a temperature of the drying is above 0.degree. C. and less than or
equal to 200.degree. C.
11. The counter electrode for dye-sensitized solar cell according
to claim 2, wherein the acid in the acid-doped polyaniline layer is
an organic functional protonic acid.
12. The counter electrode for dye-sensitized solar cell according
to claim 2, wherein the acid in the acid-doped polyaniline layer is
a sulfonic acid and/or citric acid.
Description
TECHNICAL FIELD
[0001] The present invention belongs to the technical field of
solar cells, and particularly relates to a counter electrode for
dye-sensitized solar cell and a method for manufacturing the
same.
BACKGROUND
[0002] Since 1980s, dye-sensitized solar cells have drawn great
attention from researchers. In 1991, Professor M. Gratzel and his
research group from Ecole polytechnique federale de Lausanne,
Switzerland, made a great breakthrough in the research in dye
sensitization of porous electrode. They assembled a new type of
solar cell, a dye-sensitized solar cell, using a porous titanium
dioxide (TiO.sub.2) film electrode, which is sensitized by an
organic complex dye comprising a transition metal ruthenium as a
photosensitizer, as the photoanode, iodine and lithium iodide as
the electrolyte, and a platinum electrode as the counter electrode,
and obtained a photoelectric conversion efficiency of 7.1%-7.9%
under the radiation of simulated sunlight of AM 1.5 and 100
mW/cm.sup.2. In 1993, M. Gratzel et al. further reported a
dye-sensitized nanometer solar cell having a photoelectric
conversion efficiency of up to 10%. In 1997, the photoelectric
conversion efficiency was further increased to 10-11%, and the
short-circuit current was 18 mA/cm.sup.2, and the open-circuit
voltage was 720 mV. Since then, dye-sensitized solar cells have
drawn great attention worldwide.
[0003] A dye-sensitized solar cell mainly consists of a transparent
conductive substrate, a porous nanocrystalline film, a sensitizer,
an electrolyte (I.sup.-/I.sub.3.sup.-) solution and a transparent
counter electrode. The photoelectric conversion mechanism thereof
is as follows. When sunlight reaches the cell, the dye molecules
absorb energy from sunlight, and electrons in the dye molecules are
excited and transit to an excited state. The electrons in the
excited state would be rapidly injected into the TiO.sub.2
conductive band, and the dye molecules are transformed to an
oxidized state due to loss of the electrons. The electrons injected
into the TiO.sub.2 conductive band are transmitted rapidly in the
TiO.sub.2 film, instantly reach the contact interface between the
film and the conductive glass, accumulate on the conductive
substrate, and flow to the counter electrode through an outer
circuit. The dye molecules in the oxidized state accept electrons
from the electron donor (F) in the electrolyte
(I.sup.-/I.sub.3.sup.-) solution and return to the ground state,
thereby regenerating the dye molecules. After losing its electron,
the electron donor (reductant) in the electrolyte solution diffuses
to the counter electrode and accepts an electron and is reduced. In
this way, a photoelectric chemical reaction cycle is completed. The
counter electrode is mainly used for collecting electrons,
accelerating the electron exchange rate between
I.sup.-/I.sub.3.sup.- and cathode electrons, and decreasing to the
greatest extent the probability of the recombination between
I.sub.3.sup.- and electrons in the TiO.sub.2 conductive band.
However, the currently used counter electrodes are mainly those
using platinum as the surface plating. Although this kind of
counter electrodes has good catalytic capability, platinum itself
is an expensive rare material and the manufacturing process thereof
is complex, leading to high production cost of this kind of counter
electrodes, which is not suitable for large scale production and
application. Accordingly, it has become a trend in the art to
develop new materials for counter electrodes which exhibit low cost
and high efficacy and can be used to replace platinum
electrodes.
SUMMARY
[0004] The embodiments of the present inventions provide a counter
electrode for dye-sensitized solar cell which shows high
conductivity and low cost.
[0005] In addition, a method for preparing a counter electrode for
dye-sensitized solar cell is provided.
[0006] In order to achieve the above objectives, the technical
solutions of the present invention are as follows.
[0007] A counter electrode for dye-sensitized solar cell comprises
a conductive substrate and an acid-doped polyaniline layer coated
on at least one surface of the conductive substrate.
[0008] In addition, a method for preparing a counter electrode for
dye-sensitized solar cell comprises the steps of:
providing an acid-doped polyaniline solution and a conductive
substrate; and coating the acid-doped polyaniline solution on at
least one surface of the conductive substrate, and drying to give
the counter electrode for dye-sensitized solar cell having an
acid-doped polyaniline layer coated on a surface thereof.
[0009] The counter electrode for dye-sensitized solar cell
according to the present invention comprises an acid-doped
polyaniline layer. The acid-doped polyaniline in the acid-doped
polyaniline layer has a relatively high conductivity, leading to
low surface resistance of the counter electrode and high
conductivity of the counter electrode. The acid-doped polyaniline
has a strong catalytic capability, which increases the probability
of redox reaction between I.sub.3.sup.- in the electrolyte of the
dye-sensitized solar cell comprising the counter electrode with
electrons in the outer circuit, thereby decreasing to the greatest
extent the probability of the recombination between I.sub.3.sup.-
and electrons in the conductive band. The acid-doped polyaniline
has a relatively high viscosity, which increases the binding
strength between the acid-doped polyaniline layer and the
conductive substrate, thereby further increasing the electron
transmission rate from the counter electrode to the outer circuit
as well as the conductivity. The counter electrode for
dye-sensitized solar cell has a performance which is comparative
with that of currently used platinum counter electrodes, and has
low production cost. The method for preparing the counter electrode
for dye-sensitized solar cell is simple, and the obtained counter
electrode for dye-sensitized solar cell has a stable performance.
The method exhibits high production efficiency, has low
requirements on the production equipments, and is suitable for
industrial production.
BRIEF DESCRIPTION OF THE FIGURES
[0010] FIG. 1 shows a scheme of a structure of the counter
electrode for dye-sensitized solar cell according to the present
invention;
[0011] FIG. 2 shows a scheme of another structure of the counter
electrode for dye-sensitized solar cell according to the present
invention; and
[0012] FIG. 3 shows a scheme of the flow chart of the method for
preparing the counter electrode for dye-sensitized solar cell
according to the present invention.
SPECIFIC EMBODIMENTS OF THE PRESENT INVENTION
[0013] In order to make the technical problems to be solved, the
technical solutions and the advantages of the present invention
more obvious, the present invention will be further described in
detail in combination with the Figures and the embodiments. It
shall be understood that the specific embodiments described herein
are only to illustrate rather than to limit the present
invention.
[0014] An embodiment of the present invention provides a counter
electrode for dye-sensitized solar cell which shows high
conductivity and low cost. The structures thereof are illustrated
in FIGS. 1 and 2. The counter electrode for dye-sensitized solar
cell of the present embodiment comprises a conductive substrate 1
and an acid-doped polyaniline layer 20 coated on at least one
surface of the conductive substrate 1. In this way, the counter
electrode for dye-sensitized solar cell of the present embodiment
comprises an acid-doped polyaniline layer, which comprises an
acid-doped polyaniline having relatively high conductivity, leading
to low surface resistance of the counter electrode, and increasing
the conductivity of the counter electrode. The acid-doped
polyaniline has strong catalytic ability, leading to increased
probability of redox reaction between I.sub.3.sup.- in the
electrolyte of the dye-sensitized solar cell comprising the counter
electrode with electrons in the outer circuit, thereby decreasing
to the greatest extent the probability of the recombination between
I.sub.3.sup.- and electrons in the conductive band. The acid-doped
polyaniline has a relatively high viscosity, which increases the
binding strength between the acid-doped polyaniline layer and the
conductive substrate, thereby further increasing the electron
transmission rate from the counter electrode to the outer circuit
as well as the conductivity. The counter electrode for
dye-sensitized solar cell has a performance which is comparative
with that of currently used platinum counter electrodes, and has
low production cost.
[0015] Specifically, the counter electrode for dye-sensitized solar
cell of the above embodiment can be implemented in at least two
ways as shown below.
[0016] The first way is shown in FIG. 1, wherein the counter
electrode for dye-sensitized solar cell comprises a conductive
substrate 1 and an acid-doped polyaniline layer 2 coated on one
surface of the conductive substrate 1.
[0017] The second way is shown in FIG. 2, wherein the counter
electrode for dye-sensitized solar cell comprises a conductive
substrate 1 and acid-doped polyaniline layers 2 coated on two
opposite surfaces of the conductive substrate 1. In this way, by
coating acid-doped polyaniline layers 2 on two opposite surfaces of
the conductive substrate 1, the conductivity of the counter
electrode for dye-sensitized solar cell is further improved, the
probability of the recombination between I.sub.3.sup.- in the
electrolyte of the dye-sensitized solar cell comprising the counter
electrode and electrons in the conductive band is decreased to the
greatest extent, and the electron transmission rate from the
counter electrode to the outer circuit as well as the conductivity
are further increased.
[0018] Furthermore, the thickness of the acid-doped polyaniline
layer in the above embodiment is preferably 20 nm-5 .mu.m, more
preferably 20 nm-50 m. The thickness of the acid-doped polyaniline
layer has certain effects on the photoelectric conversion
efficiency of the dye-sensitized solar cell. When the acid-doped
polyaniline layer has a thickness in the above preferred range, the
photoelectric conversion efficiency of the dye-sensitized solar
cell can be effectively improved.
[0019] Specifically, the acid in the above acid-doped polyaniline
layer is preferably a protonic acid. The protonic acid may be an
organic protonic acid or an inorganic protonic acid. The protonic
acid is preferably an organic functional protonic acid, more
preferably a sulfonic acid and/or citric acid. The sulfonic acid is
preferably at least one of camphorsulfonic acid, dodecylsulfonic
acid, sulfosalicylic acid, p-styrene sulfonic acid, p-toluene
sulfonic acid, naphthalenesulfonic acid, dinonylnaphthalenesulfonic
acid, dioctyl sulfosuccinate and sulfanilic acid. The inorganic
protonic acid is preferably least one of hydrochloric acid,
sulfuric acid and perchloric acid. The protonic acid is preferred
because protonation preferably occurs on the amine nitrogen atom in
the molecular chain, wherein the protonic acid HA dissociates and
the resulted hydrogen proton (H+) transfers to the polyaniline
molecular chain and protonates the amine nitrogen atom in the
molecular chain to give excited state polarons of charge-carrying
elements. After being doped with a protonic acid, the quinone ring
in the eigen state polyaniline disappears, the electron cloud
redistributes, and the positive charge on the nitrogen atom
delocalizes to the conjugated .pi. bonds, so that polyaniline
exhibits high conductivity. Of course, the acid may also be
selected from non-protonic acids, such as PCl.sub.5, SOCl.sub.2,
TsCl and/or AlCl.sub.3. The acid-doped polyaniline obtained by
doping with a non-protonic acid has lower conductivity than that of
the acid-doped polyaniline obtained by doping with a protonic acid.
The acid-doped polyaniline layer is prepared with the following S12
process from eigen state polyaniline and an acid which are mixed in
a mass ratio of preferably 1:2-1:5.
[0020] The material for the above conductive substrate 1 may be one
of indium-doped tin oxide glass, fluorine-doped tin oxide glass,
carbon steel, stainless steel, aluminum-doped zinc oxide,
magnesium-indium oxide, nickel-tungsten oxide, metal nitride, metal
selenide, metal sulfides, foamed copper, foamed aluminum, foamed
copper alloy and foamed aluminum alloy.
[0021] An embodiment of the method for preparing the counter
electrode for dye-sensitized solar cell of the present invention is
shown in FIG. 3. The method for preparing the counter electrode for
dye-sensitized solar cell comprises the steps of:
S1. providing an acid-doped polyaniline solution and a conductive
substrate 1 (as shown in FIG. 1); and S2. coating the acid-doped
polyaniline solution on at least one surface of the conductive
substrate 1, and drying to give the counter electrode for
dye-sensitized solar cell having an acid-doped polyaniline layer
coated on a surface thereof.
[0022] In step S1 in the above embodiment of the method for
preparing the counter electrode for dye-sensitized solar cell, the
mass concentration of the acid-doped polyaniline in the acid-doped
polyaniline solution is preferably 1-20%. The process for obtaining
the acid-doped polyaniline solution may be as follows:
S11. providing an eigen state polyaniline, an acid and a solvent;
S12. mixing the eigen state polyaniline and the acid, heating in a
water bath and/or sonicating, washing, filtering, and drying to
give an acid-doped polyaniline precursor; and S13. dissolving the
acid-doped polyaniline precursor in a solvent, and diluting to give
the acid-doped polyaniline solution.
[0023] Specifically, in step S11 in the above process for obtaining
the acid-doped polyaniline solution, the eigen state polyaniline
and the acid are mixed in a mass ratio of preferably 1:2-1:5. The
eigen state polyaniline may be commercially available. The solvent
is preferably at least one of de-ionized water, N-methyl
pyrrolidone, methanol, iso-propanol, n-butanol and ethanol. The
amount of the solvent used is preferably such that the mass
concentration of the final acid-doped polyaniline solution is
1-20%. The acid may be a pure acid liquid, e.g. an analytically
pure acid liquid, or an acid solution formulated by diluting a pure
acid liquid. The selection of the acid is described hereinbefore,
and will not be repeated for conciseness.
[0024] In step S12 in the above process for obtaining the
acid-doped polyaniline solution, the temperature for heating in a
water bath is preferably 50-100.degree. C., and the time is
preferably 8-72 h; and the time for sonicating is preferably 4-40
min. Heating in a water bath and/or sonicating are conducted to
sufficiently and homogeneously mix the eigen state polyaniline and
the acid solution, and accelerate the doping of the acid solution
into the eigen state polyaniline. The eigen state polyaniline is
not an ideal material for processing due to its poor solubility.
Accordingly, its relevant properties can be improved by doping with
an acid. For example, a large molecular organic protonic acid may
have surface activating effect and act as a surfactant, and may
significantly increase the solubility of polyaniline doped
therewith. In addition, by doping an organic protonic acid into
polyaniline, the intra-molecular and inter-molecular conformations
of polyaniline favor the delocalization of the charges in the
molecular chain, so that the conductivity of the acid-doped
polyaniline is significantly increased. On the other hand, the
process of doping with an inorganic protonic acid is simple and the
conductivity of the acid-doped polyaniline is relatively high, so
that the surface resistance of the obtained electrode is reduced.
In this step, washing, filtering and drying are conducted to remove
the excessive acid solution, and to obtain a relatively pure
acid-doped polyaniline precursor, wherein the drying may be
conducting by oven drying, air drying, sun drying, or the like.
When oven drying is employed, the temperature is preferably lower
than the melting point of the acid-doped polyaniline.
[0025] In step S13 in the above process for obtaining the
acid-doped polyaniline solution, the acid-doped polyaniline
precursor is dissolved and diluted in a solvent to facilitate
homogeneous coating of the obtained acid-doped polyaniline solution
on a surface of the conductive substrate 1 in a subsequent
process.
[0026] In step S1 in the above embodiment of the method for
preparing the counter electrode for dye-sensitized solar cell, the
material for the conductive substrate 1 is preferably one of
indium-doped tin oxide glass, fluorine-doped tin oxide glass,
carbon steel, stainless steel, aluminum-doped zinc oxide,
magnesium-indium oxide, nickel-tungsten oxide, metal nitride, metal
selenide, metal sulfides, foamed copper, foamed aluminum, foamed
copper alloy and foamed aluminum alloy.
[0027] In step S2 in the above embodiment of the method for
preparing the counter electrode for dye-sensitized solar cell, the
method for coating the acid-doped polyaniline solution on the
conductive substrate 1 is preferably spin coating, scrape coating,
silkscreen coating, or spray coating. When spin coating is employed
for coating the acid-doped polyaniline solution, the rotation speed
for the spin coating is preferably 500-4000 rpm, and the time is
preferably 15-60 seconds. After the coating is completed, the
conductive substrate 1 coated with the acid-doped polyaniline
solution is dried, so that the surface of the conductive substrate
1 is tightly bound to the acid-doped polyaniline layer 2 (as shown
in FIGS. 1 and 2). The drying process can be carried out by oven
drying, air drying or sun drying. When oven drying is employed, the
temperature is preferably above 0.degree. C. and less than or equal
to 200.degree. C.
[0028] The above embodiment of the method for preparing the counter
electrode for dye-sensitized solar cell may preferably further
comprise a step of conducting surface treatment to the conductive
substrate 1. The surface treatment conducted to the conductive
substrate 1 is preferably one or more of oxygen plasma treatment,
uv-ozone treatment, aqua regia treatment, hydrogen peroxide
treatment, acid treatment and chemical polishing treatment. The
conductive substrate 1 is surface treated to eliminate contaminants
and oxides from the surface of the conductive substrate 1, improve
wettability and adsorbability of the surface of the conductive
substrate 1, and further eliminate organic contaminants from the
surface of the conductive glass. This facilitates treatments in
subsequent processes, so that the acid-doped polyaniline layer 2
formed in subsequent processes is tightly bound to its surface, so
that the electron transfer transmission rate from the counter
electrode to the outer circuit as well as the conductivity are
further improved.
[0029] When the counter electrode for dye-sensitized solar cell of
the above embodiment is used in a dye-sensitized solar cell, the
materials and the preparation methods of other components of the
dye-sensitized solar cell, such as anode base, porous
nano-crystalline film, dye sensitizer, and electrolyte, are as
follows.
[0030] Anode base: indium-doped tin oxide glass, fluorine-doped tin
oxide glass, aluminum-doped zinc oxide, magnesium-indium oxide,
nickel-tungsten oxide, metal nitride, metal selenide, metal
sulfide, or metal base such as stainless steel plate and stainless
steel mesh.
[0031] Porous nano-crystalline film: TiO.sub.2 porous electrode
made from P25 type titanium dioxide particles, or nanometer
semi-conductive material such as ZnO, SnO.sub.2, Nb.sub.2O.sub.5
and SrTiO.sub.3; the method for preparing the porous
nano-crystalline film may any suitable one, such as scrape coating,
silkscreen coating, gelling or spray coating.
[0032] Electrolyte: a liquid electrolyte containing 0.5 mol/L KI
and 0.05 mol/L I.sub.2, or a polymeric electrolyte.
[0033] Dye sensitizer: N719, N3, black dye or some highly effective
triphenylamine-type dyes.
[0034] The present invention will be further described in detail in
combination with specific examples.
Example 1
[0035] A counter electrode for dye-sensitized solar cell has a
structure as shown in FIG. 1. The counter electrode for
dye-sensitized solar cell comprises a conductive substrate 1, and
an acid-doped polyaniline layer 2 having a thickness of 20 nm
coated on a surface of the conductive substrate 1.
[0036] The method for preparing the counter electrode for
dye-sensitized solar cell is as follows.
[0037] The mass ratio of polyaniline to p-styrene sulfonic acid is
1:3. Eigen state polyaniline is weighed and mixed with a 10 wt %
solution of p-styrene sulfonic acid. The mixture is heated in a
water bath to 50.degree. C. under stirring. After reacting for 72
hours, the mixture is washed with p-styrene sulfonic acid,
filtered, and drying to give doped polyaniline. The above
acid-doped polyaniline is sufficiently dissolved in de-ionized
water to prepare an aqueous solution of polyaniline having a mass
fraction of 1% for further use. An indium-doped tin oxide glass is
cut into the required size, and sonicated in sequence in a
detergent, de-ionized water, acetone, ethanol and iso-propanol,
each for 15 min. The washed indium-doped tin oxide glass is
subjected to an oxygen plasma treatment for 5-15 min at a power of
10-50 W. In this way, wettability and adsorbability of the surface
of the conductive glass are improved and organic contaminants on
the surface of the conductive glass are further eliminated. The
treated conductive glass is dried for further use. The prepared
aqueous solution of polyaniline is added dropwise on a spin coater,
and is spin coated on the indium-doped tin oxide glass at a spin
speed of 4000 rpm for 15 s. The coated glass is then heating in an
oven at 150.degree. C. for 40 min. After drying, the desired
counter electrode for dye-sensitized solar cell is obtained.
[0038] When the counter electrode for dye-sensitized solar cell
obtained in Example 1 is used in a dye-sensitized solar cell, the
materials and the preparation methods of other components of the
dye-sensitized solar cell, such as anode base, porous
nano-crystalline film, dye sensitizer, and electrolyte, are as
follows.
[0039] Anode base: one of indium-doped tin oxide glass,
fluorine-doped tin oxide glass, carbon steel, stainless steel,
aluminum-doped zinc oxide, magnesium-indium oxide, nickel-tungsten
oxide, metal nitride, metal selenide, metal sulfide, foamed copper,
foamed aluminum, foamed copper alloy and foamed aluminum alloy,
wherein the stainless steel may be a metallic anode base such as
stainless steel plate and stainless steel mesh; the thickness
thereof may a conventional thickness in the art.
[0040] Porous nano-crystalline film: TiO.sub.2 porous electrode
made from P25 type titanium dioxide particles; the method for
preparing the porous nano-crystalline film may any suitable one,
such as scrape coating.
[0041] Electrolyte: a liquid electrolyte containing 0.5 M KI and
0.05 M I.sub.2.
[0042] Dye sensitizer: N719.
[0043] As measured, the counter electrode for dye-sensitized solar
cell prepared in Example 1 may advantageously catalyze the redox
reaction of I.sup.-/I.sub.3.sup.-, increase the probability of
redox reaction between I.sub.3.sup.- with electrons in the outer
circuit, and decrease the probability of the recombination between
I.sub.3.sup.- and electrons in the conductive band, thereby
avoiding its recombination with electrons in the conductive band
and increasing to a great extent the photovoltaic performance of
the cell. The photoelectric conversion efficiency of the above
dye-sensitized solar cell is 5.6%, close to that of the platinum
electrode, which is 6% as measured under the same conditions.
Example 2
[0044] A counter electrode for dye-sensitized solar cell has a
structure as shown in FIG. 1. The counter electrode for
dye-sensitized solar cell comprises a conductive substrate 1, and
an acid-doped polyaniline layer 2 having a thickness of 50 nm
coated on a surface of the conductive substrate 1.
[0045] The method for preparing the counter electrode for
dye-sensitized solar cell is as follows.
[0046] The mass ratio of polyaniline to p-styrene sulfonic acid is
1:5. Eigen state polyaniline is weighed and mixed with a 4 wt %
solution of p-styrene sulfonic acid. The mixture is heated in a
water bath to 80.degree. C. under stirring. After reacting for 18
hours, the mixture is washed with p-styrene sulfonic acid,
filtered, and dried to give doped polyaniline. The above acid-doped
polyaniline is sufficiently dissolved in de-ionized water to
prepare an aqueous solution of polyaniline having a mass fraction
of 10% for further use. A fluorine-doped tin oxide glass is cut
into the required size, and sonicated in sequence in a detergent,
de-ionized water, acetone, ethanol and iso-propanol, each for 15
min. The washed glass is dried for further use. The prepared
aqueous solution of polyaniline is added dropwise on a spin coater,
and is spin coated on the fluorine-doped tin indium oxide glass at
a spin speed of 1000 rpm for 30 s. The coated glass is then heating
in an oven at 200.degree. C. for 30 min. After drying, the desired
counter electrode for dye-sensitized solar cell is obtained.
[0047] When the counter electrode for dye-sensitized solar cell
obtained in Example 2 is used in a dye-sensitized solar cell, the
materials and the preparation methods of other components of the
dye-sensitized solar cell, such as anode base, porous
nano-crystalline film, dye sensitizer, and electrolyte, are as
described in Example 1.
[0048] As measured, the counter electrode for dye-sensitized solar
cell prepared in Example 2 may advantageously catalyze the redox
reaction of I.sup.-/I.sub.3.sup.-, increase the probability of
redox reaction between I.sub.3.sup.- with electrons in the outer
circuit, and decrease the probability of the recombination between
I.sub.3.sup.- and electrons in the conductive band, thereby
avoiding its recombination with electrons in the conductive band
and increasing to a great extent the photovoltaic performance of
the cell. The photoelectric conversion efficiency of the above
dye-sensitized solar cell is 7.15%, close to that of the platinum
electrode, which is 6.9% as measured under the same conditions.
Example 3
[0049] A counter electrode for dye-sensitized solar cell has a
structure as shown in FIG. 1. The counter electrode for
dye-sensitized solar cell comprises a conductive substrate 1, and
an acid-doped polyaniline layer 2 having a thickness of 45 nm
coated on a surface of the conductive substrate 1.
[0050] The method for preparing the counter electrode for
dye-sensitized solar cell is as follows.
[0051] The mass ratio of polyaniline to p-toluene sulfonic acid is
1:4. Eigen state polyaniline is weighed and mixed with a 4 wt %
solution of p-toluene sulfonic acid. The mixture is heated in a
water bath to 100.degree. C. under stirring. After reacting for 10
hours, the mixture is washed with p-toluene sulfonic acid,
filtered, and dried to give doped polyaniline. The above acid-doped
polyaniline is sufficiently dissolved in a mixed solvent of
de-ionized water and n-butanol in a volume ratio of 1:1 to prepare
an aqueous solution of polyaniline having a mass fraction of 1% for
further use. A stainless steel base plate is cut into the required
size, washed with a detergent, subjected to a chemical polishing
treatment to eliminate oxides and contaminants from the surface,
sonicated in sequence in de-ionized water, acetone and ethanol,
each for 15 min, and dried for further use. The prepared aqueous
solution of polyaniline is added dropwise on a spin coater, and is
spin coated on the stainless steel plate at a spin speed of 500 rpm
for 60 s. The coated plate is then heating in an oven at
100.degree. C. for 60 min. After drying, the desired counter
electrode for dye-sensitized solar cell is obtained.
[0052] When the counter electrode for dye-sensitized solar cell
obtained in Example 3 is used in a dye-sensitized solar cell, the
materials and the preparation methods of other components of the
dye-sensitized solar cell, such as anode base, porous
nano-crystalline film, dye sensitizer, and electrolyte, are as
described in Example 1.
Example 4
[0053] A counter electrode for dye-sensitized solar cell has a
structure as shown in FIG. 1. The counter electrode for
dye-sensitized solar cell comprises a conductive substrate 1, and
an acid-doped polyaniline layer 2 having a thickness of 5 nm coated
on a surface of the conductive substrate 1.
[0054] The method for preparing the counter electrode for
dye-sensitized solar cell is as follows.
[0055] The mass ratio of polyaniline to perchloric acid is 1:2.
Eigen state polyaniline is weighed and mixed with pure perchloric
acid. The mixture is heated in a water bath to 50.degree. C. under
stirring. After reacting for 72 hours, the mixture is washed with
pure perchloric acid, filtered, and dried to give doped
polyaniline. The above acid-doped polyaniline is sufficiently
dissolved in methanol to prepare an aqueous solution of polyaniline
having a mass fraction of 20% for further use. A foamed copper base
plate is cut into the required size, washed with a detergent,
subjected to a chemical polishing treatment to eliminate oxides and
contaminants from the surface, sonicated in sequence in de-ionized
water, acetone and ethanol, each for 15 min, and dried for further
use. The prepared aqueous solution of polyaniline is coated on the
foamed copper base plate by silkscreen printing. The coated base
plate is then heating in an oven at 180.degree. C. for 40 min.
After drying, the desired counter electrode for dye-sensitized
solar cell is obtained.
[0056] When the counter electrode for dye-sensitized solar cell
obtained in Example 4 is used in a dye-sensitized solar cell, the
materials and the preparation methods of other components of the
dye-sensitized solar cell, such as anode base, porous
nano-crystalline film, dye sensitizer, and electrolyte, are as
described in Example 1.
Example 5
[0057] A counter electrode for dye-sensitized solar cell has a
structure as shown in FIG. 1. The counter electrode for
dye-sensitized solar cell comprises a conductive substrate 1, and
an acid-doped polyaniline layer 2 having a thickness of 20 nm
coated on a surface of the conductive substrate 1.
[0058] The method for preparing the counter electrode for
dye-sensitized solar cell is as follows.
[0059] The mass ratio of polyaniline to sulfuric acid is 1:5. Eigen
state polyaniline is weighed and mixed with a solution of sulfuric
acid. The mixture is sonicated for 40 min. After reacting for 12
hours, the mixture is washed with the solution of sulfuric acid,
filtered, and dried to give doped polyaniline. The above acid-doped
polyaniline is sufficiently dissolved in iso-propanol to prepare an
aqueous solution of polyaniline having a mass fraction of 10% for
further use. A foamed copper base plate is cut into the required
size, washed with a detergent, treated with diluted hydrochloric
acid to eliminate oxides from the surface, sonicated in sequence in
de-ionized water, acetone and ethanol, each for 15 min, and dried
for further use. The above aqueous solution of polyaniline is added
in a spray gun and is spray-coated on the foamed copper base plate
to form a polyaniline film having a homogeneous thickness. After
the coated base plate is air-dried, the desired counter electrode
for dye-sensitized solar cell is obtained.
[0060] When the counter electrode for dye-sensitized solar cell
obtained in Example 5 is used in a dye-sensitized solar cell, the
materials and the preparation methods of other components of the
dye-sensitized solar cell, such as anode base, porous
nano-crystalline film, dye sensitizer, and electrolyte, are as
described in Example 1.
Example 6
[0061] A counter electrode for dye-sensitized solar cell has a
structure as shown in FIG. 2. The counter electrode for
dye-sensitized solar cell comprises a conductive substrate 1, and
acid-doped polyaniline layers 2 having a thickness of 20 nm coated
on both surfaces of the conductive substrate 1.
[0062] The method for preparing the counter electrode for
dye-sensitized solar cell is as follows.
[0063] The mass ratio of polyaniline to a mixture of
sulfosalicyclic acid and citric acid (mass ratio: 1:1) is 1:3.
Eigen state polyaniline is weighed and mixed with a mixture of
sulfosalicylic acid and citric acid (mass ratio: 1:1). The mixture
is sonicated for 4 min, washed with sulfosalicylic acid, filtered,
and dried to give doped polyaniline. The above acid-doped
polyaniline is sufficiently dissolved in N-methyl pyrrolidone to
prepare an N-methyl pyrrolidone solution of polyaniline having a
mass fraction of 15% for further use. A magnesium-indium oxide
glass is cut into a plate having an area of 10.times.20 cm, washed
with a detergent, immersed overnight in iso-propanol to
sufficiently eliminate residue grease from the surface, sonicated
in sequence in de-ionized water, acetone and ethanol, each for 15
min, and dried for further use. The above N-methyl pyrrolidone
solution of polyaniline is scrape-coated on two opposite surfaces
of the magnesium-indium oxide glass with a glass rod to form a
polyaniline film having a homogeneous thickness. The coated glass
is cut into the required size and heated in an oven at 100.degree.
C. for 30 min. After drying, the desired counter electrode for
dye-sensitized solar cell is obtained.
[0064] When the counter electrode for dye-sensitized solar cell
obtained in Example 6 is used in a dye-sensitized solar cell, the
materials and the preparation methods of other components of the
dye-sensitized solar cell, such as anode base, porous
nano-crystalline film, dye sensitizer, and electrolyte, are as
described in Example 1.
[0065] The counter electrodes for dye-sensitized solar cell
prepared in the above Examples 1-6 are tested and verified to have
the following properties. The acid-doped polyaniline in the
acid-doped polyaniline layer has a relatively high conductivity,
leading to low surface resistance of the counter electrode and high
conductivity of the counter electrode. The acid-doped polyaniline
has a strong catalytic capability, which increases the probability
of redox reaction between I.sub.3.sup.- in the electrolyte of the
dye-sensitized solar cell comprising the counter electrode with
electrons in the outer circuit, thereby decreasing to the greatest
extent the probability of the recombination between I.sub.3.sup.-
and electrons in the conductive band. The acid-doped polyaniline
has a relatively high viscosity, which increases the binding
strength between the acid-doped polyaniline layer and the
conductive substrate, thereby further increasing the electron
transmission rate from the counter electrode to the outer circuit
as well as the conductivity. The counter electrode for
dye-sensitized solar cell has a performance which is comparative
with that of currently used platinum counter electrodes, and has
low production cost. The method for preparing the counter electrode
for dye-sensitized solar cell is simple, and the obtained counter
electrode for dye-sensitized solar cell has a stable performance.
The method exhibits high production efficiency, has low
requirements on the production equipments, and is suitable for
industrial production.
[0066] Described above are only preferred embodiments of the
present invention, which are not intended to limit the present
invention. All modifications, equivalent substitutions and
improvements within the spirit and principle of the present
invention shall be within the scope of the present invention.
* * * * *